Clean Energy Systems | Grainger College of Engineering

“Floating offshore wind farms are a very interesting and complex design problem,” he says. James Allisonprofessor of industrial and enterprise systems engineering. “My group uses advanced engineering design methods to achieve the goals of accelerating new energy technologies and reducing energy costs.”

Another DOE Energy Earthshot initiative is the Floating Offshore Wind Shot, which aims to transition densely populated coastal regions to clean energy and reduce the cost of floating offshore wind by more than 70%. About two-thirds of the U.S. offshore wind potential is located in waters that are too deep to anchor a traditional wind turbine.

Despite their potential for significant energy production, wind turbines present a unique design challenge, with systems typically designed sequentially. First, starting with aerodynamic design, such as blade design. Then moving on to structural design, such as ensuring the blades and tower are strong enough. And finally, control design, which determines things like blade pitch under various operating conditions.

“But with this sequential approach to design, we miss opportunities for synergy between these different areas,” Allison says. “Control co-design refers to the holistic design or integrated design of actively controlled engineering systems, where we simultaneously look at how we should design the physical and control aspects of the system.”

Floating offshore turbines pose an even more interesting design problem. Allison explains: “If you have a wind turbine on a floating platform, you have additional degrees of freedom and it will be more dynamic. The platform will move with the waves, ocean currents, wind and weather, whereas if you use a control system designed for onshore turbines, the floating platform will be an unstable system. We need completely different control systems for that because it is much more complicated.” Although these offshore environments are very extreme, there are also many more sources of energy at sea, making it a viable prospect.

Recent DOE-supported research at the University of Illinois has used control co-design to develop new, lightweight, and inexpensive floating wind energy systems that are robust enough to operate reliably at sea. These systems provide a cost-effective way to harness the vast energy resources of deep-sea wind.

Advanced engineering design methods like control codesign can be applied not only to floating offshore wind turbines. Allison is also investigating hydrokinetic turbines, which are smaller underwater turbines that can be placed in rivers or ocean currents. Such turbines could be installed in remote locations, such as a small village in Alaska, where grid power is not an option and residents are competing with the cost of electricity generated by a diesel generator, which is more expensive and less clean.

“I spend a lot of time looking for synergies, looking at the interface between aspects of a system,” Allison says. “An interface can be a physical interface between things, or it can be an interface between different technical disciplines. If we’re working in a more siloed approach, we often miss opportunities to improve the whole system.”